The human T-cell leukemia viruses (HTLV) are family of exogenous human retroviruses with three known types. HTLV type-I (HTLV-I) is etiologically associated with adult T-cell leukemia-lymphoma (ATL), first described clinically in Japan, and found endemic to southern Japan, the Caribbean Basin, and certain parts of Africa. HTLV type-II (HTLV-II) was isolated from a patient with a T-cell variant of hairy cell leukemia. Although serological cross-reactivity between HTLV-I and II has been reported, these two viruses differ significantly in antigen assays and in their genomes. A third subgroup of HTLV (HTLV-III) refers to a prototype virus isolated from patients with acquired immune deficiency syndrome (AIDS).
Specific antibodies to HTLV-I have been detected in ATL patients and in asymptomatic carriers. These antibodies are known to recognize both gag and env protein of the virus. Viral gag proteins have been purified, sequenced, and murine monoclonal antibodies against these core proteins (p19, P24) have been produced and extensively used for detecting core antigens. However, viral envelope proteins, important for viral infection, have not been well characterized. Murine monoclonal antibody to a minor component of envelope protein (gp21 or p20E) has been reported, but a monoclonal antibody to the major component of envelope protein (gp46) has not yet been produced. The present invention discloses the production of a monoclonal antibody which specifically binds to the major HTLV-I envelope protein (gp46). Furthermore, the present invention discloses an immortalized cell line, designated 0.5 alpha, which secretes this monoclonal antibody.